Modulation of Ca2+ and Na+ transport by taurine in heart and vascular smooth muscle

Adv Exp Med Biol. 1996:403:263-73. doi: 10.1007/978-1-4899-0182-8_28.

Abstract

Using the whole-cell voltage clamp technique, taurine was found to affect different types of various ionic currents including T and L-type Ca2+ currents, slow Na+ and fast Na+ currents as well as the delayed outward K+ current. Also, in normal situations, taurine had no effect on the Na(+)-Ca2+ exchange current. The effect of taurine on the different types of ionic currents appears to depend on [Ca2+]o and [Ca2+]i and may also vary according to the tissue or cell type studied. Using standard Ca2+ imaging techniques, short-term exposure (10 to 20 min) of single heart cells and aortic vascular smooth muscle cells was found to increase total intracellular free Ca2+ in a dose-dependent manner. However, using 3-dimensional Ca2+ and Na+ imaging techniques, long-term exposure of heart and vascular smooth muscle cells to taurine was found to decrease both nuclear and cytosolic Ca2+ without significantly changing either nuclear or cytosolic Na+ levels. Long-term exposure to taurine was found to prevent cytosolic and nuclear increases of Ca2+ induced by permanent depolarization of heart cells with high [K+]o. This preventive effect of taurine on nuclear Ca2+ overload was associated with an increase of both cytosolic and nuclear free Na+. Thus, the effect of long-term exposure to taurine on intranuclear Ca2+ overload in heart cells seems to be mediated via stimulation of sarcolemma and nuclear Ca2+ outflow through the Na(+)-Ca2+ exchanger.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Aorta, Thoracic / drug effects
  • Aorta, Thoracic / physiology*
  • Biological Transport / drug effects
  • Calcium / metabolism*
  • Calcium Channels / drug effects
  • Calcium Channels / physiology
  • Chick Embryo
  • Endothelium, Vascular / physiology
  • Female
  • Heart / drug effects
  • Heart / physiology*
  • Heart Atria
  • Humans
  • In Vitro Techniques
  • Male
  • Muscle, Smooth, Vascular / drug effects
  • Muscle, Smooth, Vascular / physiology*
  • Patch-Clamp Techniques
  • Potassium Channels / drug effects
  • Potassium Channels / physiology
  • Rabbits
  • Sodium / metabolism*
  • Sodium Channels / drug effects
  • Sodium Channels / physiology
  • Taurine / pharmacology*

Substances

  • Calcium Channels
  • Potassium Channels
  • Sodium Channels
  • Taurine
  • Sodium
  • Calcium